Brake pad with a wear indicator

Abstract

The invention relates to a brake pad (1) having a wear indicator (5). The brake pad (1) has a first bore (20) opening out into the braking face (4) of the friction lining (2), a second bore (22) opening out into the first bore (20) and into the edge (23) of the lining, and a slot (24) which extends between the first bore (20), the second bore (22), the edge (23), and the braking face (4). The indicator (5) comprises a pellet (6) adapted to the first bore (20), a sleeve (14) slidably mounted on the conductors (12a, 12b) of the indicator (5) and urged against the pellet (6) by a resilient sheath (16) that bears against the connection terminal (15) of the indicator (5). The diameter of the sleeve (14) is substantially equal to the diameter of the second bore (22). The slot (24) serves to pass the conductor wires (12a, 12b) during installation of the indicator (5) on the brake pad (1), after the sleeve (14) has been moved away from the pellet (6).

We claim: 
     
       1. A brake pad for a vehicle brake, the pad comprising a friction lining (2) and a wear indicator (5) fixed by fixing means, said indicator (5) comprising a body (6) of insulating material and an electrical conductor (10) designed to be connected to an electrical indicator circuit, a portion (9) of said conductor (10) being disposed in said body (6) in such a manner that it is itself worn by a rotary part of the brake once the friction lining (2) has been reduced to a thickness of less than a predetermined value, the brake pad being characterised by the fact that the body (6) is shaped to be received in the bottom of a first blind bore (20) formed in the friction lining (2) and opening out into the braking face (4) of said lining, by the fact that the means for fixing the indicator (5) on said lining (2) comprise a rigid sleeve (14) slidably mounted on the electrical conductor (10) in the vicinity of said body (6) and suitable for being received in a second bore (22) formed in said lining (2) and opening out into said first bore (20) and to one of the edges (23) of the lining (2), and by the fact that a slot (24) is provided in the friction lining to pass the electrical conductor (10) during installation of the wear indicator (5) on said lining (2), said slot (24) being narrower than the diameter of the sleeve (14) and extending between said first bore (20), said second bore (22), said edge (23), and said braking face (4). 
     
     
       2. A brake pad according to claim 1, characterised by the fact that means are provided for holding the sleeve in the second bore (22). 
     
     
       3. A brake pad according to claim 2, characterised by the fact that the free end of the electrical conductor (10) includes a plug (15) for connection to the electrical indicator circuit, and by the fact that the means for holding the sleeve (14) in the second bore (22) comprise a resilient sheath (16) capable of sliding over the electrical conductor and of exerting on said sleeve (14) a force (F) that is directed towards the body (6). 
     
     
       4. A brake pad according to claim 3, characterised by the fact that sleeve (14) is inserted in one end of said resilient sheath (16). 
     
     
       5. A brake pad according to claim 1, characterised by the fact that the body (6) is in the form of a pellet (6). 
     
     
       6. A brake pad according to claim 5, characterised by the fact that the pellet (6) has an annular groove (8) in its edge (7), and by the fact that the electrical conductor (20) is an insulated conductor wire forming a loop that is received in said groove (8). 
     
     
       7. A brake pad according to claim 6, characterised by the fact that the pellet (6) includes, in its edge (7), a recess (13) adapted to receive the inner end (19) of the sleeve (14). 
     
     
       8. A brake pad according to claim 1, characterised by the fact that the body is in the form of a pellet (6) provided with a radial rod (30) whose diameter is no greater than the thickness of the slot (24), said pellet (6) and said rod (30) being formed by being moulded over a portion (9, 12a, 12b) of the electrical conductor (10). 
     
     
       9. A brake pad according to claim 8, characterised by the fact that the sleeve is constituted by the end (18) of a resilient sheath (16).